Electrical interrupter



E E FREY ELECTRICAL INTERR-UPTER Filed Feb. 6, 1933 Jan. 2, 1934.

Patented Jan. 2, 1934 PATENT OFFICE ELECTRICAL INTEBRUPTER Elmer E.Frey, Los Angeles, Calif., assignor to Kittle Manufacturing 00., LosAngeles, Calif. a

corporation of California Application February 6,1933. Serial Na.655,420

Claim.

This invention relates to electrical interrupters, and. particularly tomagnetically operated contact devices for momentarily flashing anelectric lamp at predetermined intervals.

5 It is common to illuminate certain street traflic signs, such as "stopsignals, so that they will display a warning to trafiic at night as wellas during the day. Various types of electric lamps have been used forthis purpose, and in many 1. instances electromagnetically operatedflashers have been employed to flash the lamp and to make it moreeffective as a warning signal. Furthermore, because of their highefliciency and appropriate color, neon lamps have been frequentlyemployed as the source of illumination in such signs, and these lampsrequire for their operation a relatively high potential. The highpotential may be conveniently obtained by intermittently applying a lowpotential, (110 volts or less) to the primary winding of a transformer,the secondary of which is connected to the neon tube. Each time theprimary circuit is closed and opened the sudden change in the magneticflux produced in the transformer develops a high potential in thesecondary winding sufficient to flash the neon lamp.

Various types of interrupters may be employed for periodically closingand opening the electrical circuit in an illuminated sign of the typedescribed, probably the simplest being magnetically operated contactsactuated by the current to be interrupted. A difficulty has been toobtain a simple interrupter that is inexpensive to make, reliable inoperation, requires little maintenance, and opens and closes the circuitat the desired intervals.

An object of the invention is to provide an interrupter having theatom-mentioned desirable characteristics.

Other more specific objects and'features of the invention will beapparent from the following detailed description which refers to thedrawing.

In the drawing:

Figure 1 is-a front elevation view of the interrupter in accordance withthe invention, with the cover plate broken away to show the mwhanism.

Figure 2 is a side elevation view of the same device.

Figure 3 is a detailed view of the oscillatable element of theinterrupter illustrating the operation of the device.

Figure 4 is a schematic diagram illustrating a circuit in which myinterrupter may be used.

The assembly disclosed in the drawing is particularly intended formounting within a tubular 5 column such as may be used to support anilluminated tramc signal employing a neon lamp. Thus there is shown inthe drawing a tubular transformer case 1 which may be suspended within atubular column and which supports apanel 2 upon which the interrupterproper is mounted, 60 the panel 2 being suspended below the transformerhousing 1.

The panel 2 is preferablyconstructed of insulating material, and hasmounted thereon an electromagnet 3 and an oscillatable disc 4. The disc4 is secured to a horizontal central shaft 5, which is supported at itsfront and rear ends, respectively, in pivot bearing screws 6 and '7,respectively. Thus the screws 6 and 7 are provided with depressions intheir inner ends to receive the pivot ends of the shaft 5 and arethreaded into a U-shaped supporting member 8 which is secured to thepanel 2; Disc 4 is provided at its periphery with a segment 9 ofparamagneticmaterial, such as iron, and with a counterbalance 10 ofnon-magnetic material, on'the opposite side, for substantiallycounterbalancing the weight of the paramagnetic material. A weight 11 isalso secured to the disc adjacent its periphery for unbalancing the discand causing it to assume a desired normal position of rest, in whichposition, of course, the weight 11 is in lowermost position,

In the operation of the interrupter, disc 4 is positively oscillatedbyenergizing the electromagnet 3 at intervals to periodically attractthe paramagnetic element 9, which will hereinafter be referred to as thearmature. The electrical circuit for energizing the electromagnet 3 isshown in Fig. 4 and comprises a pair of contacts 12 and 13,respectively, connected in series with the electromagnet 3 and a pair ofterminals 14 and 15, respectively, which, in turn, may be connected toan external circuit includinga source of potential (shown as a 110 -voltlighting circuit) and a device to be operated by the interrupted currentwhich is shown in Fig. 4 as a transformer 16, the secondary of which isconnected to a neon tube 17.

Referring now to Figs. 1, 2 and 3, the contac 13 comprises a fixedcontact anchored to the supporting base 2, and the contact 12 is securedto one end of a lever 18 which is pivotally mounted to oscillate about apivot 19 secured to the base. The end of lever 18, to which the contact12 is secured, is relatively short, as shown, and the opposite endextends down in a slanting position in front of the disc 4. Because ofthe length and weight of the lower end of the lever 18, the latternormally occupies a position in which the contact 12 is forced intocontact with the fixed contact 13.

1i flexible connection 20 is provided to make electrical connectionbetween contact 12 and a binding post 21 secured to the panel 2. Bindingpost 21 is connected by a wire 22 extending back of the panel 2, to thebinding post 15.

Disc 4 is provided with a pin 23 projecting forwardly from the facethereof for engagement with the lower end of lever 18 when the disc isoscillated in a counterclockwise direction, to move the lever 18 in aclockwise direction about its pivot 19, and open the contacts 12 and 13.Pin 23, therefore, serves to open the electrical circuit of theelectromagnet' 3 and de-energize it as the armature 9 reaches a positionopposite the pole piece of the magnet 3, thereby permitting the disc tocontinue its oscillation, carrying the armature 9 a substantial distancepast the pole piece. The limit of movement of the disc 4 in acounterclockwise direction, after the opening of the contacts 12 and 13,is determined by the weight of the balancing member 11 or bya-springstop member 24 extended up in front of the disc, which stopmember intercepts a pin 27 projecting from the disc if the latter movessufiiciently far. After reaching the limit of its movement in acounterclockwise direction, the disc reverses its movement because ofthe weight of the balancing member 11 and the armature 9 moves back pastthe pole of the electromagnet. However, if no stop means were providedto prevent it, the contacts 12 and 13 would again close as soon as thepin 23 moves out of contact with the lower end of lever 18 and thedirection of oscillation of the disc would be immediately reversed bythe attracrotation of the disc 4 it just clears the upper end,

of spring 25. However, when the disc 4 has moved sufliciently far in acounterclockwise direction to bring the pin 27 adjacent the lower end ofspring 25, the pin 23 has contacted the lever 18 and has moved thelatter, together with the spring 25, outwardly so that the lower end ofthe spring 25 barely strikes the pin 27 and is deflected inwardlythereby, to permit passage of the spring past the pin. Thereafter, whenthe disc reverses its direction of oscillation and moves back in a clockwise direction, the pin 2'7 intercepts the inner side of the lower endof spring 25 (Fig. 3) and moves spring 25 and lever 18 outwardly, thepin 27 sliding along the inner surface of spring 25 as the disc rotates.Pin 27 therefore maintains the spring 25 and the lower end of lever 18in such a position that the contact 12 is maintained out of contact withthe fixed contact 13 until the continued rotation of the disc 4 ina-clockwisedirection carries the pin 27 past the upper end of spring 25.Spring 25 and lever.18 are thereupon released to fall into theirlowermost normal position of rest, in which the contacts 12 and 13 areclosed to energize the electromagnet 3. By this time, however, the disc4 has substantially completed its oscillation in a clockwise direction,in which the armature 9. is in the position shown in Fig. 1.

'From the foregoing description, it will be apparent that upon theinitial closure of the external energizing circuit, the armature 9 isattracted by the electromagnet, thereby imparting an impulse to the disc4 to rotate the latter in a counterclockwise direction, this impulsecontinuing and the disc being accelerated until the armature 9 is in aposition opposite the pole piece of the electromagnet, when the pin 23strikes the lower end of lever 18 and opens the contacts 12 and 13,thereby opening the circuit and de-energizing the electromagnet. Thedisc then continues to rotate in a counterclockwise direction by virtueof its own inertia until its movement is stopped either by the weight ofthe balancing member 11, or by the pin 27 striking the spring stopmember 24. It thereafter reverses its direction of oscillation andaccelerates in the opposite direction because of the weight of themember 11, which tends to return to'its lowermost position. Since theinitialcounterclockwise movement of the disc carried the pin 27 past thelower end of spring 25, the latter deflecting to permit the pin 27 topass, when the disc reverses, and the pin 27 moves back, it interceptsthe end of spring 25 and lifts the latter, together with the lower endof lever 18, to prevent the contacts 12 and 13 closing until the discreaches its normal position of rest (the position shown in Fig. 1) whenthe pin 27 leaves the upper end of spring 25 and permits the lower endof lever 18 to drop and close the contacts 12 and 13. This energizes theelectromagnet 3 which again attracts the armature 9 andrepeats the cycleof operation just described.

Since the electromagnet 3 is energized immediately upon closure of thecontacts 12 and 13, the armature 9 is immediately attracted by themagnet and swings the disc to bring pin 23 against lever 18 and reopenthe contacts. Therefore, the time during which the contacts 12 and 13are closed is relatively small as compared to the total time requiredfor a complete oscillation of the disc. This makes the device economicalof current.

The operation of oscillation of the disc 4, and therefore the timeinterval between consecutive closures, may be adjusted between widelimits by varying the weights of the armature 9 and the counterbalance10, and of the member 11. Thus increasing the weights of the armature 9and the counterbalance 10 decreases the speed of oscillation, whereasincreasing the weight of the-member 11 decreases the period ofoscillation.

A condenser 28 is preferably bridged across the binding posts '14 and 15to reduce sparking at the contacts 12 and 13 resulting from inductivereactance in the external circuit to which the interrupter is connected.

Having fully described the preferred embodiment of this invention, it isto be understood that I do not limit myself to the exact constructionherein set forth, which may obviously be varied in detail withoutdeparting from the spirit of this invention, but only as set forth inthe appended claims.

I claim:

1; An electrical interrupter comprising an oscillatable member, anelectromagnet adjacent the path of oscillation of said member for urgingsaid member in one direction during a substantial portion of the travelof said member, a pair of contacts for opening and closing theenergizing circuit of said electromagnet, a movable arm for opening saidcontacts in response to movement in one direction and closing them inresponse to movement in the other direction, said arm normally seeking aposition in which said contacts are closed, means movable in responsenosaoss to movement of said oscillatable member for shifting saidmovable arm to open said contacts during a predetermined portion of themovement of said oscillatable member in one direction at least, andother means for preventing return movement of said arm into position toclose said contacts during an additional portion of the movement of saidmember when the latter is moving in one direction only.

2. In an electrical interrupter, an oscillatable member comprising anarmature adapted to oscillate in a predetermined path between first andsecond end positions, an electromagnet positioned adjacent the path ofmovement of said armature intermediate the ends of said path, means forurging said armature toward said first end position, a pair of contactsfor opening and closing the energizing circuit for said electromagnet, amovablearm for closing and .opening said contacts, said arm normallyseeking a position in which said contacts are closed, said oscillatablemember comprising means for impinging against and shifting said arm toopen said contacts while said armature is in that portion oi? its pathextending from a point adjacent said electromagnet to its second endposition, and additional means operable only during movement of .saidarmature from said second to said first end position for preventingcontact-closing movement of said arm until said armature hassubstantially reached its first end position.

3. An electrical interrupter as described in claim 2, in which said lastmeans comprises a fiat spring secured at one end to said arm, and acooperating pin on the oscillatable member, said one end of said springmember being nearer the first end of said path than is the free end ofthe spring and being out of the path of movement of said pin and thefree end extending across the path of movement whereby the pin passes onone side of the spring during movement of the oscillatable member fromsaid first to said second end positions, deflecting the free end of thespring as it passes it, but engages the opposite face of the free end ofthe spring on its return movement,

and delays contact-closing movement of said arm until the pin has movedthe'length of the spring.

'4. An electrical interrupter comprising a disc pivoted to rotate aboutits axis in a vertical plane, an electromagnet mounted adjacent theperiphcry of said disc, an armature comprising a segment of paramagneticmaterial secured to said disc for movement with said disc past saidelectromagnet, means for completing a circuit to said electromagnetcomprising a fixed contact and a movable contact, an arm extendingslantingly downward across the face of said disc and pivoted formovement in a plane parallel to said disc, said movable contact beingmounted upon said arm and being normally maintained against said fixedcontact by the weight of said arm, a pin extending from the face of saiddisc for engaging with and lifting said arm to separate said contactswhen said armature oscillates past said eiectromagnet in one directionand maintaining them separated while the armature is completing itsmovement in that direction and returning to the electromagnet, and aresilient arm attached to said arm and extending approximately parallelthereto, and a second pin extending from the face of said disc and sopositioned on said disc as to intercept said resilient arm and maintainsaid arm in raised position following the release of said arm by saidfirst mentioned pin during return movement of said disc, said pindeflecting said resilient arm inwardly with respect to said firstmentioned arm and slippin past the end thereof during the movement ofsaid disc in said one direction.

5. An electrical interrupter comprising an oscillatable member, anelectromagnet adjacent the path of oscillation of said member for urgingsaid member in one direction during a substantial portion of the travelof said member, a pair of contacts for opening and closing theenergizing circuit of said electromagnet, movable contactaetuating meansfor opening said contacts in response to movement of said means in onedirection and closing them in response to movement of said means intheother direction, said means normally seeking a position in which saidcontacts are closed, means movable in response to movement of saidoscillatable member for shifting said contact-actuating means to opensaid contacts during a predetermined portion of the movement of saidoscillatable member in one direction at least, said contact-actuatingmeans comprising a resilient strip, and a projection on saidoscillatabie member positioned to pass adjacent one side of the saidstrip and deflect and slip by the free end of said strip during movementof said oscillatable member in said one direction and to intercept theother side of said strip and prevent movement 'of said contact-actuatingmeans into position to 'ciow said contacts during a portion 01 thereturn movement only of said oscillatable member.

. ELMER E. FREE.

